Lubricants containing phosphosulfurized polyolefin-amide reaction products



United States Patent 4 Claims. ci. 252-325 This invention relates to oil compositions comprising a base oil containing a novel phosphorusand sulphurcontaining additive derived from carbonic acid, and also relates to processes for preparing the said novel additive for incorporation in lubricating oils.

The compositions of this invention are characterized in having improved detergent and dispersant properties, and also are stable in that little or no hydrogen sulphide is given off during storage. Thus, the compositions of this invention are eminently suitable for use in internalcombustion engines using a lubricating base oil for preventing formation of sludge, varnish, and other deposits, in inhibiting wear and corrosion in such engines. The compositions may also be used for other purposes as hereinafter described.

It has previously been proposed to add to oils various additives for improving the detergent and/or dispersant or anti-oxidant properties of the oil. Thus metal-containing additives such as metal sulphonates and phenols have commonly been used. Such metal-containing additives are at a disadvantage when used .in high-performance internal combustion engines, as being conducive to the formation of ash, with resultant falling off of engine efiiciency due to such phenomena as preignition, knocking, plug fouling and ring seizure.

Non-metal-containing additives have also been proposed for lubricating oils. Phosphosulphurized hydrocarbons have been used, but it has been found that amongst other disadvantages, such additives tend to generate hydrogen sulphide during storage or use, which besides imparting a disagreeable odour to the lubricating oil, also encourages corrosion of the bearings and other engine parts. This defect can only be partly remedied by incorporating with such phospho-sulphurized hydrocarbons auxiliary additives such as guanidine, quaternary ammonium compounds, terpenes, or derivatives thereof.

It has now been discovered that oil compositions containing an additive as hereinafter described have improved detergent and dispersant properties and are stable. To this end, the invention consists of olcaginous fluids containing an oil-soluble additive obtained by phosphosulphurizing a hydrocarbon, and further reacting the phosphosulphurized product with an amide of carbonic acid.

The compositions of this invention are particularly suitable for use in internal combustion engines when the base oil is a lubricating oil and contains from 0.1 to 5% by Weight of the said additive. However compositions according to this invention also consist of concentrates containing substantially greater proportions of the additive, which may then be diluted with further base oil.

The additive contained in the oil according to this invention is a phosphosulphurized hydrocarbon further reacted with an amide of carbonic acid.

The hydrocarbon from which the additive is derived may be a parafiin, olefin, olefin polymer, diolefin, petroleum fraction, including cracked fractions and napht-henic fractions, bright-stock residua, lubricating oil fractions, paraffin waxes and the bottoms from the fractionated products of UOP polymerization processes. The preferred hydrocarbons are brightstoclcs and poly-olefins, for

"ice

instance isobutylene having a molecular weight between 200 and 10,000, particularly between 600 and 3,000.

The hydrocarbons are phosphosulphurized prior to reaction with the amide of carbonic acid, using any phosphorus sulphide, for instance P 8 or alternatively a mixture of elemental phosphorus and sulphur may be used. The phosphosulphurization step may be carried out at elevated temperatures between about and 600 F., preferably between 300 and 550 F. The time of reaction may vary between about /2 hour to 10 hours, according to the degree of reaction required. Thus 1 to 10, preferably 2 to 5 mols of hydrocarbon may be reacted with one mol of phosphorus pentasulphide. The reaction is preferably carried out in a non-oxidising atmosphere, for instance in nitrogen.

After the desired degree of phosphosulphurization has taken place, the product is then further reacted with an amide of carbonic acid, which may alternatively be defined as a derivative of carbamic acid. Examples of such derivatives are carbamic compounds represented by the general formula:

N t O=C/ wherein R is hydro-gen or an alkyl group containing 1 to 20 carbon atoms. Specific compounds which may be used are urethane and urea, or the corresponding thio derivatives, e.g., thiourea and ammonium carbamate.

The reaction with the carbonic acid amide may be carried out at elevated temperatures from 250 F. to 350 F., preferably between 285 and 340 F. The amide is gradually added to the reacting mass over a period of time from A1 to 10 hours preferably from 1 to 3 hours, until the required amount of amide has been reacted with the phosphosulphurized hydrocarbon. to 3 mols of amide are used.

Greater storage stability is provided for the final additive if the phosphosulphurized hydrocarbon is steamstripped prior to reaction with the amide. Thus the phosphosulphurized hydrocarbon may be contacted with steam at a temperature of about 285 to 325 F. for a period of time to bring the acid number of the mixture to a value preferably above 25, or the sulphur content of the phosphosnlphurized hydrocarbon less than 1.5%. Thus the steaming may be continued for from 2 to 5 hours, the quantity of steam used is preferably between 10% to 20% by weight of the phosphosulphurized hydrocarbon.

The \oleaginous fluid may be any animal, vegetable, mineralv or synthetic oil. Thus petroleum oil fractions ranging from naphthas through spindle oil to SAE 30, 40 or 50 lubricating oil grades may be used as the base oil, or caster oil, or fish oils, or oxidized mineral oil, diesters, complex esters or other synthetic oils may be used.

The oil compositions of this invention may contain other additive constituents which are commonly added to lubricating or fuel oils. Thus, toil-soluble anti-oxidant compounds may be incorporated, for instance ccor B-naphthylarnine, phenothiazine, including alkyl-substituted derivatives thereof, alkyl phenols, for instance 2,4- di methyl-Gdertiary octyl phenol, substituted dipheny-lamines, including di-octyl diphenylamine, and bisphenols. Extreme-pressure additives such as alkylor aryl-substituted phosphates and phosphites, sulphurized hydrocarbons, 'sulphurized sperm oil, or metal di-alkyl dithiophosphates may be included in the compositions, as may polyiso-olefins or degraded rubbery copolymers and other compounds which act as viscosity improvers or tackiness agents. I

While compositions according to this invention are particularly suitable for use as lubricating compositions for Preferably from 1.5

Example I An additive concentrate according to this invention was prepared by heating 100 parts by weight of polyisobutylene of molecular weight 960 with 15 parts by weight of P S for 6 hours at a temperature of 430 F. The resulting product was diluted with 100 parts by weight of mineral lubricating oil, the solution thus obtained had an acid number of 13.

The solution was then steam-stripped by bubbling steam through the oil at a temperature of 320 F. for 8 hours, when the acid number was raised to 39. The resulting product was reacted with 5% by weight, based on the total solution, of urea, added slowly and continuously over a period of 1 hour, and the whole kept at an elevated temperature of 430 F. and subsequently filtered.

Analysis of the final product according to the invention showed the following results:

Percent Sulphur content 0.13 Phosphorus content 1.74 Nitrogen content 1.2

Comparative engine tests were conducted using a 2% solution of the additive concentrate of Example I in a mineral oil having a viscosity at 210 F. of 11.6 cs., and a viscosity index of 138. The tests were carried out in a Peugeot 403 engine having 4 cylinders of bore 80 cm.,

and 73 mm. stroke, having a total capacity of 1468 cc.,

and a compression ratio of 7:1.

The test runs consisted of 25 six-hour cycles, giving a total of 150 hours under test, each cycle consisting of three periods in which the engine ran under the following conditions:

Engine Oil Tem- Time, Period Speed perai ure, hours After the total time of test, the cleanliness of working parts were assessed on a merit scale of from 0 to 100, 100 being assigned to parts with no deposits and 0 being assigned to parts entirely covered by deposits. The results of these tests are given in Table I:

TABLE I Base oil with Base oil with Parts no additive additive according to invention Valves 68 70. 8 Piston rings 91 94. 8 Overall cleanliness 98 99. 2

by bubbling CO through an oil solution a neutralized acidic phosphosulphurized hydrocarbon in the presence of an alkyl phenol colloid stabilizer.

Particularly useful combinations are provided by incorporating in the compositions of this invention small proportions, e.g., 0.1 to 10% by weight, based on the total composition, of a non-metal-containing copolymer derived from at least one alkyl ester of an oc-,B unsaturated carboxylic acid and a polymerizable monomer containing an oxygen-or nitrogen-containing polar group.

Such copolymers are preferably derived from alkyl esters of '5 unsaturated monoor di-carboxylic acids, in-

cluding acrylates, methacrylates, itaconates, fumarat'es' and maleates. Particularly preferred tripolymers are derived from C -C alkyl diesters of fumaric or maleic acid, esters of vinyl alcohol and a C -C monocarboxylicv acid, and a po'lymerizable monomer containing an oxygenor nitrogen-containing polar group diiferent from the aforesaid esters. Examples of nitrogen-containing polar compounds are ethylenically unsaturated nitriles, N-vinyl butyrolactams (for example, N-vinyl pyrrolidone) and pyridines. Examples of oxygen-containing polar compounds are maleic anhydride, and half-esters of maleic acid, in which the remaining acid group is reacted with 1 to 10 molecules of an alkylene oxide, for instance ethylene oxide.

To illustrate the synergistic eifect produced by the combination hereinbefore described, reference may be made to the following examples of the compositions according to this invention, and also of compositions containing an auxiliary detergent-dispersant compound.

Example ll An SAE 30 type mineral lubricating oil containing 2% by weight of the concentrate of Example I.

Example 111 TABLE II l Example 11 Example III Sludge demerit at 33 hours. Nil- Sludge demerit at 66 hours- 3% l Sludge demerit at 99 hours 7% 4% Sludge demerit at, 132 hours 8 1 Engine failed due to excess sludge.

It will be noted that the presence of an auxiliary dispersant copolymer in the compositions of this invention resulted in an improvement in the amount of sludge deposited in the engine.

What is claimed is:

1. A lubricating oil composition for use in sparkignited internal combustion engines, having reduced tendencies toward forming engine deposits, comprising a major amount of a mineral lubricating oil and a minor amount in the range of about 0.1 to 5 wt. percent of an oil-soluble lubricating oil additive for inhibiting engine deposits, prepared by heating together above 250 F. (a) a phosphosulfurized polyolefin having a molecular weight in therange of 200 to 10,000 and (b) an amide of carbonic acid selected from the group consisting of urea, urethane, thiourea, and ammonium carbamate in a mole ratio of (a) to (b) of about 1/1.5 to about 1/3.

2. A lubricating oil composition as defined in claim 1 wherein said polyolefin is polyisobutylene having a molecular weight of about 960, and (b) is urea.

3. A lubricating oil as defined in claim 1 containing about 0.1 to 5.0 wt. percent of an oil-soluble auxiliary dispersant copolymer derived from (1) esters of fumaric acid and C to C aliphatic alcohols, (2) vinyl acetate, and (3) N-vinyl pyrrolidone.

4. A process for preparing an improved mineral lubricating oil composition comprising reacting at a temperature in the range of 190 F. to 600 F. 1 to 10 mols of a polyolefin having a molecular Weight in the range of 200 to 10,000 with one mol of a phosphorus sulfide, dissolving the product in mineral oil, steam stripping the resulting solution at a temperature in the range of 285 F. to 325 F. for a period of time until the acid number of said solution rises above 25, and reacting the product thereby obtained at a temperature in the range of 250 F. to 350 F. with 1.5 to 3.0 mols, based upon the phosphosulfurized polyolefin, of an amide of carbonic acid selected from the group consisting of urea, urethane, thiourea and ammonium carbamate.

References Cited by the Examiner UNITED STATES PATENTS 2,712,528 7/1955 Hill et al 25246.6 2,742,429 4/1956 Verley 25246.7 2,798,045 7/1957 Buck et a1 25232.7 2,900,376 8/1959 Sobol et al 252466 X FOREIGN PATENTS 758,203 8/ 1956 Great Britain. 808,665 2/ 1959 Great Britain.

DANIEL E. WYMAN, Primary Examiner.

JULIUS GREENWALD, Examiner.

J. R. SEILER, -L. G. XIARHOS, Assistant Examiners. 

1. A LUBRICATING OIL COMPOSITION FOR USE IN SPARKIGNITED INTERNAL COMBUSTION ENGINES, HAVING REDUCED TENDENCIES TOWARD FORMING ENGINE DEPOSITS, COMPRISING A MAJOR AMOUNT OF A MINERAL LUBRICATING OIL AND A MINOR AMOUNT IN THE RANGE OF ABOUT 0.1 TO 5 WT. PERCENT OF AN OIL-SOLUBLE LUBRICATING OIL ADDITIVE FOR INHIBITING ENGINE DEPOSITS, PREPARED BY HEATING TOGETHER ABOVE 250*F. (A) A PHOSPHOSULFURIZED POLYOLEFIN HAVING A MOLECULAR WEIGHT IN THE RANGE OF 200 TO 10000 AND (B) AN AMIDE OF CARBONIC ACID SELECTED FROM THE GROUP CONSISTING OF UREA, URETHANE, THIOUREA, AND AMMONIUM CARBAMATE IN A MOLE RATIO OF (A) TO (B) OF ABOUT 1/1.5 TO ABOUT 1/3. 